Valve for rock drills



NOV. 12, 1929. w SMITH, JR 1,734,985

vArlvE FOR ROCK DRILLS Filed Feb. 15, 1929 Uy ai H15 ATTORNEY Patented Nov. 12, 1929 UNITED STATES PATENT OFFICE WILLIAM A. SMITH, JR., OF PHILLIPSBURG, NEW JERSEY, ASSIGNOR T0 INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY VALVE r03 noon mums Application filed February 15, 1929.. Serial No. 340,262.

' the cycle of operations so that the drill may be actuated with a minimum consumption of pressure fluid.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing illustrating a practical ap plication of the invention and in which similar reference characters refer to similar parts,

Figure 1 is a sectional elevation of a rock drill equipped with a valve constructed in accordance with the practice of the invention and showing the valve in one of its limiting positions, and

Figure 2 is a view similar to Figure 1 showing the valve in another limiting position.

Referring to the drawings, A. represents a cylinder having a piston chamber B in which is disposed a reciprocatory hammer plston C. The cylinder A has a free exhaust port D which is controlled b the piston C.

A closure is provi ed for the front end of the piston chamber B in the form of a front cylinder washer E having in this instance a bore F to receive slidably an anvil block G. The anvil block has a stem H projecting into the front end of the piston chamber B to receive the blows of the hammer piston C. The function of the anvil block G is to transmit the blow of the hammer piston to a working implement designated by J and extending through a front head K seated against the front cylinder washer E whereby the cylinder A and the front head K are centralized with respect to each other.

In the rearward end of the cylinder A is an enlarged bore L in which is disposed valve mechanism designated generally by O, and into the extreme rearward end of the bore L extends a projection P of a back head Q which serves as a closure for the rearward end of the cylinder.

Among other functions the back head Q,

serves as a housing for a throttle valve B whereby the admission of pressure fluid into the drill is controlled. Preferably the throttle valve R is of the rotary type having a lever S whereby it may be manipulated.

The pressure fluid for actuating the drill may be conveyed thereto through a suitable connection (not shown) and such pressure fluid may be introduced into a central chamber T of the throttle valve R. In the side of the throttle valve R is a port U adapted to register with a passage V in the back head leading in this instance to a supply reservoir W also in the back head.

The valve mechanism constructed in accordance with the practice of the invention comprises an intermediate plate X bearing with its front end against a back cylinder Washer Y which serves as a closure for the rearward end of the piston chamber B and with its rearward end against a plate Z which acts as a seat for the back head Q.

The parts comprising the casing of the drill, such as the cylinder A, the front and back heads K and Q respectively, may be held suitably clamped together by means of the usual spring pressed side rods (not shown);

When thus secured together, the back head will be pressed firmly against the plates comprising the valve chest and will thus also serve to hold these elements firmly in the 0perative position.

Formed in the lates X and Z, and in this instance also in the back head Q, is a valve chamber 3) comprising an enlarged portion 0 and a reduced portion d. The reduced portion d may as shown be formed in the plate Z and in the backhead Q and the enlarged portion 0 is formed in the plate X. The pressure fluid for actuating the piston G is admitted into the enlarged portion a of the valve chamber intermediate its ends and is conveyed thereto by a supply passage e leading from the supply reservolr W.

Pressure fluid passes from the valve chamber 39 to the front end of the piston chamber B through an inlet passage 7 and to the rearward end of the piston chamber B through a rearward inlet passage 9. Preferably the inlet passage 7 opens into the valve chamber early 6 at a point near the rearward end of the enlarged portion 0 of said valve chamber and the inlet passage 9 0 ens into portion of the valve cham the front end thereof.

The distribution of pressure fluid to the ends of the piston chamber is controlled by a valve designated by it. The valve it is spool type having a body portion 7' and a pair of flanges is and 0. The flange o is formed at the foremost end of the valve h, and the flange is at a point intermediate the ends of the valve. Both flanges k and 0 are of the same diameter and lie within the enlarged portion 0 of the valve chamber. The flanges la and 0 are so disposed with respect to the outlet opening of the supply passage e that pressure fluid will constantly be admitted into the valve chamber 6 in the space between the said flanges 7c and 0.

The rearward end of the body portion j extends into the reduced portion a. of the valve chamber 6 and serves as an actuating surface p against which pressure fluid constantly acts tending to throw the valve h forwardly. The pressure fluid utilized for this purpose is conveyed into the reduced portion'd through a port or passage g leading from. the supply reservoir W.

The front end of the flange 0 serves as an actuating surface 1? against which pressure fluid acts for throwing the valve 71. rearwardly. The pressure fluid utilized for this pur pose is conveyed into the front end of the er at a point near valve chamber 6 by a leak passage 8 in the flange 0 which is in constant communication with the supply of pressure fluid in the space between the flanges is and 0.

From the front end of the valve chamber 6 to a point in the piston chamber B forwardly of the exhaust port D leads a tripper passage t. The tripper passage 25 is in constant communication with the leak passage 8 so that pressure fluid will be constantly flowing into said tripper passage t and when such pres sure fluid is entrapped in the tripper passage by the piston C, it will act against the actuating surface a for throwing the valve rearwardly.

The outlet opening it of the tripper passage 15 may be conveniently located to obtain an i or late movement of the valve it, that is, if the outlet opening it be located near the front end of the piston, it will be covered by the piston at a later period in the stroke of said piston and consequently the rearward movement of the 'valve it will be somewhat delayed. Conversely-if the tripper passage 1. opens into the piston chamber B at a point near the exhaust port D, it will be covered earlier by the piston C and the pressure fluid entrapped therein will therefore retract the valve h at an earlier period during the for ward stroke of the iston.

The operation of the device is as follows:

the same of the G the pressure fluid acting against With the valve h ll the position illustrated in Figure 1, pressure fluid flowing from the supply reservoir W into the valve chamber will flow over the rearward surface of the flange 0 through the inlet passage 9 into the rearward end of the piston chamber B to drive the piston C forwardly against the anvil block At the same time pressure fluid will be flowing through the leak passage 5 into the front end of the valve chamber 6, thence through the tripper passage 25 into the front end of the piston chamber B from whence it may flow to the atmosphere through the exhaust port D.

The pressure fluid flowing into the tripper passage t will follow these channels until the exhaust port I) is'coveredby the piston C. lVhen the piston C covers the outlet opening it of the tripper passage 15 and entraps the pressure fluid in the tripper passage, such pressure fluid will act against the actuating surface r and whenit becomes of suficient value to overcome the pressure acting against the actuating surface 39, the valve it will be thrown rearwardly to the position illustrated in Figure 2.

In the new position of the valve, pressure fluid will flow over the forward surface of the flange is into the inlet passage 7 and the front end of the piston chamber B for actuating the piston G rearwardly. The valve it will remain in the retracted position until the piston C uncovers the exhaust port D on the rearward stroke of the piston. When this takes place, the pressure fluid in the front end of the valve chamber 6 will escape to the atmosphere through theexhaust port D and the actuat- 111g surface p will again throw the valve it to its initial position.

I claim: g p

1. In a fluid actuated rock bination of a cylinder and a haust port in the cylinder, inlet passages leading her to the cylinder,

drill, the compiston, an exa valve chamber, from the valve chama valve in the valve chamber having a pair of flanges to control the inlet passages, an actuating surface on the valve constantly exposed to pressure fluid tending to throw the valve in one direction, a second actuating surface on the valve of greater area than the first saidactuating sur face, a tripper passage leading from the valve chamber to.the cylinder and controlled b the piston, and a leak passage constantly a mitting pressure fluid into the tripper passage wherein such pressure fluid is entrap ed by the piston to act against the actuating surface of greater area for throwing the valve in the other direction.

2. In a fluid actuated rock drill, the combination of a cylinder and a piston, an exhaust port in the cylinder controlled by the piston, a valve cham er, inlet passages leading from the valve chamber to the cylinder, a

valve in the valve chamber having a pair of flanges of the same diameter to control the inlet passages, an actuating surface on one end of the valve constantly exposed to pressure fluid for throwing the valve in one direction, a second actuating surface at the other end of the valve and of larger diameter than the first said actuating surface, a tripper passage leading from the valve chamber to the cylinder and controlled by the piston, and a leak passage in one flange constantly admitting pressure fluid into the tripper passage wherein such pressure fluid is entrapped by the iston to act against the actuating surface of greater area for throwing the valve in the other direction.

' In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JR. 

